In conveyor systems for conveying small articles, such as video cassette boxes, it is often desired to stack the articles in a side by side relation and convey the stacks to working equipment or a storage site. Frequently, a conveyor system will include a group of stacking stations, each operating to stack articles into individual stacks and the stacks are then transferred to a main conveyor. The transfer mechanism is programmed so that the stacks are transferred to the main conveyor without interference from other stacks moving on the conveyor.
U.S. patent application Ser. No 07/118,534, filed Nov. 9, 1987, now U.S. Pat. No. 4,861,226, describes an apparatus for stacking articles and transferring the stacks onto a main conveyor. In the system of the aforementioned patent application individual articles are transferred from an infeed conveyor to a stacking station where the articles are stacked against a movable stop. When a stack of desired size has been formed, the stack is pushed across a horizontal surface to a discharge station which is located laterally of a main conveyor. The stack is then transferred laterally from the discharge station to the main conveyor.
With the stacking apparatus as disclosed in the aforementioned application it is necessary to return the pusher mechanism to its original position before a second stack can be formed at the stacking station. While this system operates satisfactorily at lower speeds, it is often desired to provide a system which can operate at higher speeds.